Head to head
ST vs QW For light moderate heavy
Verdict · measured basis
Qwen2.5 72B Instruct costs $0.0002 per solved task against
Step 3.5 Flash at $0.0031 — ▼ 20x cheaper .
Over 200 tasks that is $0.59 a month.
On output token price alone Step 3.5 Flash looks 1.3x cheaper. The ranking reverses once you divide by pass rate — the cheaper tokens do not win the task.
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Verified pricing, pass rate and cost per solved task for Step 3.5 Flash and Qwen2.5 72B Instruct Figure Step 3.5 Flash Qwen2.5 72B Instruct Input $/Mtok $0.1 $0.36 Output $/Mtok $0.3 $0.4 Cached input $/Mtok $0.1 $0.36 Pass rate 50% 53% Cost per solved task $0.0031 measured $0.0002 measured Cost per month $0.62 $0.03
Cost per month against tasks per month · drag the marker
Monthly cost against tasks per month Log-log lines for Qwen2.5 72B Instruct (measured, $0.0002 per solved task), Step 3.5 Flash (measured, $0.0031 per solved task) from 10 to 100,000 tasks a month. Marker at 200 tasks. 10 100 1k 10k 100k $0.001 $0.01 $0.1 $1 $10 $100 TASKS / MONTH (log) → 200 tasks Qwen2.5 72B Instruct · MEASURED · $0.0002 per solved task $0.03 Qwen2.5 72B Instruct MEASURED Step 3.5 Flash · MEASURED · $0.0031 per solved task $0.62 Step 3.5 Flash MEASURED Monthly cost against tasks per month Log-log lines for Qwen2.5 72B Instruct (measured, $0.0002 per solved task), Step 3.5 Flash (measured, $0.0031 per solved task) from 10 to 100,000 tasks a month. Marker at 200 tasks. 10 100 1k 10k 100k $0.001 $0.01 $0.1 $1 $10 $100 TASKS / MONTH (log) → 200 tasks Qwen2.5 72B Instruct · MEASURED · $0.0002 per solved task $0.03 Step 3.5 Flash · MEASURED · $0.0031 per solved task $0.62 — Qwen2.5 72B Instruct · MEASURED — Step 3.5 Flash · MEASURED Solid measured · dashed modeled · dotted stale. The gap is the verdict.
Solvency Bench (solvency.dev) — first-party measurement · verified 2026-08-26 · prices from each provider's pricing page; measured rows ignore the tier · Methodology · All models at these settings